Management of carriers to help ensure QoS for single-carrier UEs

ABSTRACT

Disclosed are methods and systems to facilitate management of carriers to help ensure QoS for single-carrier UEs. In particular, a base station may serve one or more first user equipment devices (UEs) on just a first carrier. While doing so, the base station may determine that each of the one or more first UEs being served on just the first carrier is receiving threshold low quality of service from the base station on the first carrier. Responsive to this determining, the base station may (i) select one or more second UEs based on the one or more second UEs being served by the base station on both the first carrier and one or more other carriers and (ii) discontinue serving each selected second UE on the first carrier while continuing to serve each selected second UE on one or more other carriers.

REFERENCE TO RELATED APPLICATION

This is a continuation of U.S. patent application Ser. No. 14/844,502,filed Sep. 3, 2015, the entirety of which is hereby incorporated byreference.

BACKGROUND

Unless otherwise indicated herein, the description provided in thissection is not itself prior art to the claims and is not admitted to beprior art by inclusion in this section.

A typical cellular wireless network includes a number of base stationseach radiating to define a respective coverage area in which userequipment devices (UEs) such as cell phones, tablet computers, trackingdevices, embedded wireless modules, and other wirelessly equippedcommunication devices, can operate. In particular, each coverage areamay operate on one or more carriers each defining a respective frequencybandwidth of coverage. In turn, each base station may be coupled withnetwork infrastructure that provides connectivity with one or moretransport networks, such as the public switched telephone network (PSTN)and/or the Internet for instance. With this arrangement, a UE withincoverage of the network may engage in air interface communication with abase station and may thereby communicate via the base station withvarious remote network entities or with other UEs served by the basestation.

Further, a cellular wireless network may operate in accordance with aparticular air interface protocol (radio access technology), withcommunications from the base stations to UEs defining a downlink orforward link and communications from the UEs to the base stationsdefining an uplink or reverse link. Examples of existing air interfaceprotocols include, without limitation, Orthogonal Frequency DivisionMultiple Access (OFDMA (e.g., Long Term Evolution (LTE) and WirelessInteroperability for Microwave Access (WiMAX)), Code Division MultipleAccess (CDMA) (e.g., 1×RTT and 1×EV-DO), and Global System for MobileCommunications (GSM), among others. Each protocol may define its ownprocedures for registration of UEs, initiation of communications,handover between coverage areas, and other functions related to airinterface communication.

In accordance with the recent version of the LTE standard, for instance,each coverage area of a base station may operate on one or more carriersspanning 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, or 20 MHz, with eachcarrier being divided primarily into subcarriers spaced apart from eachother by 15 kHz. The air interface is then divided over time into acontinuum of 10-millisecond frames, with each frame being furtherdivided into ten 1-millisecond subframes or transmission time intervals(TTIs) that are in turn each divided into two 0.5-millisecond segments.And each 0.5 millisecond segment or in each 1 millisecond TTI, the airinterface is then considered to define a number of 12-subcarrier wide“resource blocks” cooperatively spanning the frequency bandwidth (i.e.,as many as would fit in the given frequency bandwidth). In addition,each resource block is divided over time into symbol segments of 67 μseach, with each symbol segment spanning the 12-subcarriers of theresource block and thus supporting transmission of symbols in “resourceelements.”

The LTE air interface then defines various channels made up of certainones of these resource blocks and resource elements. For instance, onthe downlink, certain resource elements across the bandwidth arereserved to define a physical downlink control channel (PDCCH) forcarrying control signaling from the base station to UEs, and otherresource elements are reserved to define a physical downlink sharedchannel (PDSCH) for carrying bearer data transmissions from the basestation to UEs. Likewise, on the uplink, certain resource elementsacross the bandwidth are reserved to define a physical uplink controlchannel (PUCCH) for carrying control signaling from UEs to the basestation, and other resource elements are reserved to define a physicaluplink shared channel (PUSCH) for carrying bearer data transmissionsfrom UEs to the base station.

In a system arranged as described above, when a UE enters into coverageof a base station, the UE may engage in attach signaling with the basestation, by which the UE would register to be served by the base stationon a particular carrier. Through the attach process and/or subsequently,the base station and supporting LTE network infrastructure may establishfor the UE one or more bearers, essentially defining logical tunnels forcarrying bearer data between the UE and a transport network such as theInternet. Each such bearer, for instance, may include a radio-linkportion extending between the UE and the base station, and anaccess-network portion extending between the base station and a gatewayor switch that provides connectivity with the transport network.

With this arrangement, the UE may operate in a “connected” mode in whichthe base station may schedule data communication to and from the UE onthe UE's established bearer(s). In particular, when the UE has data totransmit to the base station, the UE may transmit a scheduling requestto the base station, and the base station may responsively allocate oneor more upcoming resource blocks on the PUSCH to carry that bearertraffic and transmit on the PDCCH to the UE a downlink controlinformation (DCI) message that directs the UE to transmit the bearertraffic in the allocated resource blocks, and the UE may then do so.Likewise, when the base station has bearer traffic to transmit to theUE, the base station may allocate PDSCH resource blocks to carry thatbearer traffic and may transmit on the PDCCH to the UE a DCI messagethat directs the UE to receive the bearer traffic in the allocatedresource blocks, and the base station may thus transmit the bearertraffic in the allocated resource blocks to the UE. Moreover, LTE alsosupports uplink control signaling on the PUCCH using uplink controlinformation (UCI) messages. UCI messages can carry scheduling requestsfrom UEs, requesting the base station to allocate PUSCH resource blocksfor uplink bearer data communication.

In another arrangement, a revision of LTE known as LTE-Advanced maypermit a base station to serve a UE with “carrier aggregation,” by whichthe base station schedules bearer communication with a UE on multiplecarriers at a time. With carrier aggregation, multiple carriers fromeither contiguous frequency bands or non-contiguous frequency bands canbe aggregated to increase the bandwidth available to the UE. Currently,the maximum bandwidth for a data transaction between a base station anda UE using a single carrier is 20 MHz. Using carrier aggregation, a basestation may increase the maximum bandwidth to up to 100 MHz byaggregating up to five carriers.

When carriers are aggregated, each carrier may be referred to as acomponent carrier. Of the component carriers, one may be deemed aprimary component carrier or primary cell (PCell) on which the basestation serves the UE, and each other component carrier may be deemed tobe a secondary component carrier or secondary cell (SCell) on which thebase station serves the UE. In particular, the primary carrier may bethe carrier on which the UE is attached with the serving base stationand may thus carry control signaling (such as scheduling requests andDCI messages) between the base station and the UE, in addition tocarrying scheduled data transmissions between the base station and theUE. Each added secondary carrier may then function to increase the totalbandwidth on which the base station serves the UE with scheduled datatransmissions.

OVERVIEW

In an example wireless communication system, a base station may have aradio-link layer connection respectively with each of a plurality of UEsand may thus serve each such UE over its respective radio-link layerconnection. When serving UEs in this manner, the base station'sradio-link layer connection with some of the UEs (hereafter “first UEs”)may encompass just a single first carrier. Whereas, the base station'sradio-link layer connection with other UEs (hereafter “second UEs”) mayencompass this same first carrier as well as one or more other carriers.This may specifically involve the base station serving each such secondUE with carrier aggregation service using the first carrier and one ormore other carriers.

When the base station serves the first UEs, at least some of these firstUEs may sometimes receive a relatively poor Quality of Service (QoS) onthe first carrier. For example, each such first UE may receive on thefirst carrier a QoS level that is below a threshold QoS level (e.g.,established via manual engineering input). When a first UE receives sucha relatively poor QoS, this relatively poor QoS may lead to delays incommunications between the first UE and the base station and/or may leadto interruptions to such communications, among other undesirableoutcomes.

In practice, to increase the QoS level for each first UE that receivesthe relatively poor QoS, the base station may perhaps provide additionalnetwork resources (e.g., resource blocks) to each such first UE. Forexample, the base station may establish carrier aggregation service foreach first UE that receives the relatively poor QoS on the firstcarrier, so as to provide additional carriers with which to serve eachsuch first UE. Providing additional network resources to each first UEin this manner may allow the base station to then communicate with eachfirst UE on these additional network resources while also allowing thebase station to stop communicating with each first UE on at least someof the network resources of the first carrier, thereby potentiallyincreasing the QoS level that each such first UE receives on the firstcarrier. Unfortunately, however, this approach may still not be idealbecause each such first UE may only temporarily receive a relativelypoor QoS on the first carrier and may thus not necessarily need theadditional carriers after such a first UE no longer receives therelatively poor QoS on the first carrier. As a result, providingadditional carriers in this manner may lead to unnecessary consumptionof network resources, among other undesirable outcomes.

Disclosed herein is an arrangement to help overcome problems resultingfrom first UEs that receive a relatively poor QoS on the first carrierand to do so without necessarily having to provide additional carriersto such first UEs. In accordance with the disclosure, the base stationmay serve one or more first UEs on just the first carrier and, whiledoing so, the base station may determine that each of the one or morefirst UEs being served on just the first carrier is receiving thresholdlow QoS from the base station on the first carrier, such as by receivinga QoS level that is below the above-mentioned threshold QoS level. Oncethe base station determines that each of the one or more first UEs beingserved on just the first carrier is receiving threshold low QoS from thebase station on the first carrier, the base station may responsivelyselect one or more second UEs due to the one or more second UEs beingserved by the base station on both the first carrier and one or moreother carriers. Then, after selecting one or more second UEs, the basestation may discontinue serving each selected second UE on the firstcarrier while continuing to serve each selected second UE on one or moreother carriers.

With this approach, the base station may discontinue scheduling andengaging in communications with each selected second UE on the firstcarrier, which may ultimately free up network resources on the firstcarrier. The base station may then use these network resources on thefirst carrier to schedule and engage in communications with the one ormore first UEs, which may increase the QoS level that each of the one ormore first UEs receives from the base station on the first carrier.Moreover, since the base station also serves each selected second UEwith one or more other carriers, the base station may still continueproviding service to each selected second UE, such as by continuing toschedule and engage in communications with each selected second UE onone or more other carriers. In this manner, the base station may solveproblems resulting from first UEs that receive a relatively poor QoS onthe first carrier and may do so without necessarily having to provideadditional carriers to such first UEs.

Accordingly, disclosed herein is a method that involves a base stationserving one or more first UEs on just a first carrier. The method alsoinvolves the base station determining that each of the one or more firstUEs being served on just the first carrier is receiving threshold lowquality of service from the base station on the first carrier.Responsive to the determining, the method then involves the base station(i) selecting by the base station one or more second UEs based on theone or more second UEs being served by the base station on both thefirst carrier and one or more other carriers and (ii) discontinuing bythe base station serving each selected second UE on the first carrierwhile continuing to serve each selected second UE on one or more othercarriers.

Further, disclosed herein is a wireless communication system including abase station and a controller configured to cause the base station toperform operations. These operations may involve serving one or morefirst UEs on just a first carrier frequency. Also, these operations mayinvolve determining that each of the first UEs being served on just thefirst carrier frequency is receiving threshold low quality of servicefrom the base station on the first carrier frequency. Additionally,these operations may involve, responsive to the determining, (i)selecting one or more second UEs based on the one or more second UEsbeing served by the base station on both the first carrier frequency andone or more other carrier frequencies and (ii) discontinuing serving ofeach selected second UE on the first carrier frequency while continuingto serve each selected second UE on one or more other carrierfrequencies.

Yet further, in another respect, disclosed is a non-transitorycomputer-readable medium having stored thereon instructions executableby a processor to cause a wireless communication system to carry outfunctions such as those noted above, to facilitate management ofcarriers to help ensure QoS for single-carrier UEs.

These as well as other aspects, advantages, and alternatives will becomeapparent to those of ordinary skill in the art by reading the followingdetailed description, with reference where appropriate to theaccompanying drawings. Further, it should be understood that thedescriptions provided in this overview and below are intended toillustrate the invention by way of example only and not by way oflimitation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of a wireless communication systemin which the present method can be implemented.

FIG. 2 is a simplified block diagram of a base station in which thepresent method can be implemented.

FIG. 3 is a flowchart illustrating a method to facilitate management ofcarriers to help ensure QOS for single-carrier UEs, in accordance withan example embodiment.

DETAILED DESCRIPTION

The present method and system will be described herein in the context ofLTE. However, it will be understood that principles of the disclosurecan extend to apply in other scenarios as well, such as with respect toother air interface protocols. Further, even within the context of LTE,numerous variations from the details disclosed herein may be possible.For instance, elements, arrangements, and functions may be added,removed, combined, distributed, or otherwise modified. In addition, itwill be understood that functions described here as being performed byone or more entities may be implemented in various ways, such as by aprocessor executing software instructions for instance.

Referring to the drawings, FIG. 1 is a simplified block diagram of awireless communication system in which the present method can beimplemented. In particular, FIG. 1 depicts a representative LTE network10, which functions primarily to serve UEs with wireless packet datacommunication service, including possibly voice over Internet Protocol(VoIP) service, but may also provide other functions. As shown, the LTEnetwork 10 includes at least one example LTE macro base station 12 knownas an eNodeB, which has an antenna structure and associated equipmentfor providing an LTE coverage area in which to serve one or more UEs 14.More specifically, the eNodeB 12 radiates to define one or more wirelessair interfaces 16 through which the eNodeB 12 may respectivelycommunicate with one or more served UEs 14 via the downlink and theuplink.

As shown in FIG. 1 , the eNodeB 12 has a communication interface with aMobility Management Entity (MME) 18. The MME 18 can function as asignaling controller for the LTE network 10. Further, the eNodeB 12 hasa communication interface with a serving gateway (SGW) 20, which in turnhas a communication interface with a packet-data network gateway (PGW)22 that provides connectivity with a packet-switched network 24, and theMME 18 has a communication interface with the SGW 20. In particular, theeNodeB 12 may be communicatively linked with a core network, which maybe operated by a wireless service provider. The core network thenprovides connectivity with one or more MMES, such as MME 18, as well asone or more gateways such as SGW 20 and PGW 22.

FIG. 2 is next a simplified block diagram of a representative basestation 200 such as eNodeB 12, illustrating some of the components thatcan be included in such an entity. As shown in FIG. 2 , therepresentative base station 200 may include a wireless communicationinterface 202 and a controller 204. Additionally, these components ofthe base station 200 may be communicatively linked together by a systembus, network, or other connection mechanism 26. Alternatively, they maybe integrated together in various ways.

As shown, wireless communication interface 202 may include an antennaarrangement 28, which may be tower mounted, and associated componentssuch as a power amplifier 30 and a cell site modem 32 for engaging inair interface communication with UEs via the antenna arrangement 28, soas to transmit data and control information to the UEs and receive dataand control information from the UEs. Additionally, controller 204 mayinclude processing unit 34 and data storage 36 and is arranged to manageor carry out various functions such as those discussed herein.

Processing unit 34 may then comprise one or more general purposeprocessors (e.g., microprocessors) and/or special-purpose processors(e.g., digital signal processors and/or application specific integratedcircuits) and may be integrated in whole or in part with the wirelesscommunication interface 202. And data storage 36 may include one or morevolatile and/or non-volatile storage components, such as magnetic,optical, flash, or other types of non-transitory computer readablemedia, and may be integrated in whole or in part with processing unit34.

As shown, data storage 36 may hold (e.g., have encoded thereon) programinstructions 38, which may be executable by processing unit 34 to carryout various controller functions. As such, the processing unit 34programmed with instructions 38 may define part or all of a controllerfor controlling operation of the base station 200. Alternatively oradditionally, however, such control functionality could be providedexternal to the base station 200, in another entity (e.g., separate fromthe base station 200) such as by a base station control entity (e.g.,MME 18), which may be communicatively linked with the base station andmay serve to control certain aspects of base station operationgenerally.

As noted above, the present disclosure provides for a process that isused to facilitate management of carriers to help ensure QoS forsingle-carrier UEs. This process could be carried out by eNodeB 12itself and/or by one or more other network entities, such as withportions of the analysis carried out by an entity outside of the eNodeB12 (e.g., MME 18) and the eNodeB 12 then responsively working to managecarriers. For simplicity, however, the process will be described here ina scenario where the eNodeB 12 carries out all aspects of the process.

Referring again to FIG. 1 , we may assume by way of example (and withoutlimitation) that one or more UEs 14 are each attached with eNodeB 12 andare thus each being served with wireless communication service by eNodeB12. As such, we may assume that each UE 14 has worked with eNodeB 12 toestablish a Radio Resource Control (RRC) connection defining arespective radio-link layer connection between a respective UE 14 andthe eNodeB 12, and that at least one logical bearer has been establishedbetween the respective UE 14 and the PGW 22, with the bearer including aradio portion extending between the respective UE 14 and the eNodeB 12and an access-network portion extending between the eNodeB 12 and thePGW 22 via the SGW 20.

Further, we may also assume that the eNodeB 12 has established with eachof one or more first UEs (e.g., from among the one or more UEs 14) arespective radio-link layer connection that encompasses just a firstcarrier. So when the eNodeB 12 serves each first UE, the eNodeB 12 mayschedule and engage in communications with a first UE on just the firstcarrier. Moreover, we may also assume that the eNodeB 12 has alsoestablished with each of one or more second UEs (e.g., from among theone or more UEs 14) a respective radio-link layer connection thatencompasses the same first carrier as well as one or more othercarriers. So when the eNodeB 12 serves each second UE, the eNodeB 12 mayschedule and engage in communications with a second UE on the firstcarrier and on one or more other carriers.

With regard to these second UEs, we may also assume that the eNodeB 12has worked to configure for each second UE a respective carrieraggregation service that serves each second UE using the first carrierand one or more other carriers. In this regard, the eNodeB 12 may serveeach second UE with carrier aggregation service using the same firstcarrier, but the eNodeB 12 may use as one or more other carriers in thecarrier aggregation service for each second UE either (i) the samecarrier(s) as those used by other second UEs or (ii) differentcarrier(s) than those used by other second UEs.

As the eNodeB 12 serves the first and second UEs, the eNodeB 12 maydetermine a QoS that each UE receives on each carrier. In practice, theeNodeB 12 may use various metrics to define the QoS. For example, suchmetrics may include throughput, packet loss, jitter, and/or voicequality, among others. With this arrangement, the eNodeB 12 may beconfigured to determine whether a UE is receiving threshold low QoS fromthe eNodeB 12 on a particular carrier, such as by determining whetherthe UE is receiving on the particular carrier a QoS level (e.g., a levelof at least one metric) that is below a threshold level (e.g.,established via manual engineering input). Other arrangements are alsopossible.

According to an example implementation, the eNodeB 12 may determine thateach of the one or more first UEs being served on just the first carrieris receiving threshold low QoS from the eNodeB 12 on the first carrier.Once the eNodeB 12 determines that each of the one or more first UEsbeing served on just the first carrier is receiving threshold low QoSfrom the eNodeB 12 on the first carrier, the eNodeB 12 may responsivelyseek to increase the QoS level that each such first UE is receiving fromthe eNodeB 12 on the first carrier. To do so, the eNodeB 12 mayresponsively select one or more second UEs based on the one or moresecond UEs each being served by the eNodeB 12 on both the first carrierand one or more other carriers. And once the eNodeB 12 selects the oneor more second UEs in this manner, the eNodeB 12 may then discontinueserving each selected second UE on the first carrier while continuing toserve each selected second UE on one or more other carrier.

As noted, the eNodeB 12 may select the one or more second UEs in thismanner because the eNodeB 12 may ultimately free up some networkresources on the first carrier once the eNodeB 12 discontinues theserving of each selected second UE on the first carrier. Optimally, theeNodeB 12 may then use these network resources to schedule and engage incommunications with the one or more first UEs on the first carrier,which may increase the QoS level that each such first UE is receivingfrom the eNodeB 12 on the first carrier. Moreover, since the eNodeB 12also serves each selected second UE with one or more other carriers, theeNodeB 12 may still continue providing service to each selected secondUE on those one or more other carriers.

When selecting the one or more second UEs, the eNodeB 12 may determinein various ways whether the eNodeB 12 serves a given UE on both thefirst carrier and one or more other carriers. By way of example, whenthe eNodeB 12 establishes or reconfigures a radio-link layer connectionfor a UE, the eNodeB 12 may store or otherwise update a context recordfor the UE in order to indicate that the eNodeB 12 is serving the UE 14on one or more particular carriers. To do so, the eNodeB 12 may, forinstance, store a global identifier (e.g., Absolute Radio FrequencyChannel Number (ARFCN)) of each of the one or more particular carriers.With this arrangement, the eNodeB 12 may refer to stored context recordsof various UEs to determine which of these UEs the eNodeB 12 serves onboth the first carrier and one or more other carriers, and the eNodeB 12may then select one or more second UEs based on these stored contextrecords. Other examples are also possible.

In some implementations, the eNodeB 12 may specifically select the oneor more second UEs based on the one or more second UEs being served bythe eNodeB 12 with carrier aggregation service using the first carrieras a secondary carrier and another carrier (i.e., a carrier other thanthe first carrier) as a primary carrier. The eNodeB 12 may optimallymake an initial selection in this manner so as to avoid having todiscontinue the serving of each selected second UE on the first carrierwhen this first carrier is the primary carrier of each such selectedsecond UE, or so as to otherwise avoid having to reconfigure carrieraggregation service of each selected second UE to encompass anothercarrier as the primary carrier for each selected UE. In suchimplementations, the eNodeB 12 may determine in various ways whether theeNodeB 12 serves a given UE with carrier aggregation service using thefirst carrier as a secondary carrier and another carrier as a primarycarrier.

By way of example, when eNodeB 12 facilitates carrier aggregationservice for a UE on two or more carriers, the eNodeB 12 may store orotherwise update the context record for this UE by designating one suchcarrier with a special primary carrier index (e.g., an index of 0) todenote this carrier as the primary carrier and by designating each othercarrier with a special secondary carrier index (e.g., any of 1 to 7 areused as an index respectively to identify each secondary carrier) todenote each such other carrier as a secondary carrier. With thisarrangement, the eNodeB 12 may refer to stored context records ofvarious UEs to determine which of these UEs the eNodeB 12 serves withcarrier aggregation service using the first carrier as a secondarycarrier and another carrier as a primary carrier. Other examples arealso possible.

In some cases, the eNodeB 12 may initially make a determination ofwhether the eNodeB 12 is serving at least one second UE with carrieraggregation service using the first carrier as a secondary carrier andanother carrier as a primary carrier. The eNodeB 12 may do so becausethe eNodeB 12 may sometimes not serve any UEs with carrier aggregationservice using the first carrier as a secondary carrier and anothercarrier as a primary carrier, yet the eNodeB 12 may still need to takeactions to increase the QoS level for the first UEs as noted above. Assuch, if the determination is that the eNodeB 12 is serving at least onesecond UE in this manner, then the eNodeB 12 may responsively select theat least one second UE based on the at least one second UE being servedby the eNodeB 12 with carrier aggregation service using the firstcarrier as a secondary carrier and another carrier as a primary carrier.Whereas, if the determination is that that the eNodeB 12 is not servingat least one second UE with carrier aggregation service in this manner,then the eNodeB 12 may responsively instead select one or more othersecond UEs based on the one or more other second UEs each being servedby the eNodeB 12 with carrier aggregation service using the firstcarrier as a primary carrier and one or more other carriers as secondarycarriers.

In such cases, if the eNodeB 12 ends up selecting one or more second UEsbased on the one or more second UEs being served by the eNodeB 12 withcarrier aggregation service using the first carrier as a primary carrierand one or more other carriers as secondary carriers, the eNodeB 12 mayseek to avoid discontinuing the serving of each selected second UE onthe primary carrier. To avoid discontinuing the serving in this manner,the eNodeB 12 may reconfigure respective carrier aggregation service foreach selected second UE to use another carrier as the primary carrier.By way of example, the eNodeB 12 may do so by engaging in handoverprocessing in order to transition a UE to being served by anothercarrier as the primary carrier or may do so in other ways. Afterreconfiguring respective carrier aggregation service for each selectedsecond UE to use another carrier as the primary carrier, the eNodeB 12may end up serving each selected second UE with carrier aggregationservice using the first carrier as a secondary carrier or may end upremoving the first carrier altogether from each such carrier aggregationservice, among other possibilities. Regardless, once the eNodeB 12reconfigures the carrier aggregation service in this manner, the eNodeB12 may then discontinue the serving of each selected second UE on thefirst carrier.

According to various implementations, the eNodeB 12 may use varioustechniques to discontinue the serving of each selected second UE on thefirst carrier while continuing to serve each selected second UE on oneor more other carriers. In one example, the eNodeB 12 may discontinuescheduling and engaging in communications with each selected second UEon the first carrier while continuing to schedule and engage incommunications with each selected second UE on one or more othercarriers. For instance, the eNodeB 12 may discontinue allocation ofPDSCH resource blocks and/or PUSCH resource blocks on the first carrierto carry bearer traffic for each selected second UE while continuing toallocate PDSCH resource blocks and PUSCH resource blocks to carry bearertraffic on one or more other carriers for each selected second UE.

In some implementations, the eNodeB 12 may discontinue scheduling andcommunicating with each selected second UE on the first carrier, thoughthe eNodeB 12 may still maintain the first carrier in the radio-linklayer connection of each selected second UE. To do so, the eNodeB 12 maytransmit to a UE control signaling through a control plane protocolstack that is arranged to organize data carried between the eNodeB 12and UEs. In particular, the eNodeB 12 may transmit via this controlplane protocol stack a specific control signal that includes a binaryvalue of one (“1”) to denote activation of a secondary carrier or abinary value of zero (“0”) to denote deactivation of a secondarycarrier. This control signal may also include a secondary carrier indexto specify the secondary carrier being activated or deactivated for aspecific UE and perhaps may also include an identifier of the specificUE, among other possibilities. With this approach, the eNodeB 12 mayalso update a context record for the specific UE to indicate activationor deactivation of certain secondary carriers, so that the eNodeB 12 canthen refer to the updated context record to determine whether it ispermitted to schedule and communicate with the specific UE on certainsecondary carriers.

Further, activation in this manner may indicate to the specific UE thatthe eNodeB 12 is permitted to schedule and communicate with the specificUE on the activated secondary carrier while deactivation in this mannermay indicate to the specific UE that the eNodeB 12 is no longerpermitted to schedule and communicate with the specific UE on thedeactivated secondary carrier, though this deactivation may stillmaintain the specified secondary carrier in the radio-link layerconnection of the specific UE. With this technique, the eNodeB 12 canthen discontinue scheduling and communicating with each selected secondUE on the first carrier while maintaining the first carrier in theradio-link layer connection of each selected second UE.

In another example, the eNodeB 12 may altogether remove from theradio-link layer connection of each selected second UE the first carrierwhile maintaining one or more other carriers in the radio-link layerconnection of each selected second UE. To do so, the eNodeB 12 and eachsecond UE may engage in RRC configuration messaging and/or otherprocessing to modify each second UE's radio-link layer connection to nolonger include the first carrier. In particular, the eNodeB 12 maytransmit to each second UE an RRC connection reconfiguration messagethat specifies an updated set of carriers on which the eNodeB 12 willserve a respective second UE, such as by identifying each carrier by arespective global identifier for instance. In doing so, the eNodeB mayomit identification of the first carrier so that the first carrier isremoved from each respective radio-link layer connection. Other examplesare also possible.

In a further aspect, if discontinuing the serving of each selectedsecond UE on the first carrier still does not solve the QoS problem forthe first UEs, the eNodeB 12 may take further actions to solve the QoSproblem. For example, as noted, the eNodeB 12 may optimally make aninitial selection of the one or more second UEs based on the one or moresecond UEs being served by the eNodeB 12 with carrier aggregationservice using the first carrier as a secondary carrier and anothercarrier as a primary carrier. In this example, after the eNodeB 12discontinues serving each selected second UE on the first carrier, theeNodeB 12 may make a further determination that at least one of thefirst UEs being served on just the first carrier is still receivingthreshold low quality of service from the eNodeB 12 on the firstcarrier.

In response to this further determination, the eNodeB 12 may take moresubstantial action of additionally selecting one or more second UEsbased on the one or more second UEs being served by the base stationwith carrier aggregation service using the first carrier as a primarycarrier and one or more other carriers as secondary carriers. Whenselecting one or more additional second UEs in this manner, the eNodeB12 may reconfigure respective carrier aggregation service for eachadditionally selected second UE to use another carrier as the primarycarrier and may do so in the manner discussed above or may do so inother ways. Regardless, once the eNodeB 12 selects these one or moreadditional second UEs, the eNodeB 12 may discontinue the serving of eachadditionally selected second UE on the first carrier while continuing toserve each additionally selected second UE on one or more othercarriers. In this manner, the eNodeB 12 may free up further networkresources on the first carrier and the eNodeB 12 may then optimally usethese further network resources when serving first UEs, so as toultimately solve the QoS problem of those first UEs.

In yet a further aspect, after the eNodeB 12 discontinues serving eachselected second UE on the first carrier, the eNodeB 12 may initiate atimer that defines a duration of time for which the eNodeB 12 shoulddiscontinue serving each selected second UE on the first carrier. Oncethe timer expires, the eNodeB 12 may detect expiration of the time andmay then responsively begin to again serve each selected second UE onboth the first carrier and on one or more other carriers. By way ofexample, this may involve transmitting to a selected second UE via thecontrol plane protocol stack a control signal that includes the binaryvalue of one (“1”) to denote activation (reactivation) of the firstcarrier and perhaps may also involve updating a context record for thisselected second UE so as to denote the activation (reactivation). Otherexamples are also possible.

In this aspect, once the eNodeB 12 begins to again serve each selectedsecond UE on both the first carrier and on one or more other carriers,the eNodeB 12 may determine whether each first UE is still experiencingthe above-mentioned QoS problem and may responsively take actions basedon whether each first UE is still experiencing a QoS problem. Forexample, if the eNodeB 12 determines that each of the first UEs beingserved on just the first carrier is no longer receiving threshold lowquality of service from the eNodeB 12 on the first carrier, then theeNodeB 12 may simply resume the serving of each selected second UE onboth the first carrier and on one or more other carriers. Whereas, ifthe eNodeB 12 determines that at least one of the first UEs being servedon just the first carrier is still receiving threshold low quality ofservice from the eNodeB 12 on the first carrier, then the eNodeB 12 mayresponsively again take actions to free up network resources on thefirst carrier, such as in any of the ways discussed above. Other aspectsare also possible.

FIG. 3 is next a flowchart illustrating a method 300, which depicts anexample set of operations that can be carried out by a wirelesscommunication system in an implementation of this process. Inparticular, illustrative methods, such as method 300, may be carried outin whole or in part by component(s) and/or arrangement(s) in a wirelesscommunication system, such as by the one or more of the components ofthe representative LTE network 10 shown in FIG. 1 and/or with one ormore of the components of the base station 300 shown in FIG. 2 .However, it should be understood that example methods, such as method300, may be carried out by other entities or combinations of entities aswell as in other arrangements, without departing from the scope of thedisclosure.

Accordingly, as shown by block 302 in FIG. 3 , method 300 involves abase station serving one or more first UEs on just a first carrier. Atblock 304, method 300 then involves the base station determining thateach of the one or more first UEs being served on just the first carrieris receiving threshold low quality of service from the base station onthe first carrier. At block 306, method 300 then involves, responsive tothe determining, the base station (i) selecting one or more second UEsbased on the one or more second UEs being served by the base station onboth the first carrier and one or more other carriers and (ii)discontinuing serving each selected second UE on the first carrier whilecontinuing to serve each selected second UE on one or more othercarriers.

Exemplary embodiments have been described above. Those skilled in theart will understand, however, that changes and modifications may be madeto these embodiments without departing from the true scope and spirit ofthe invention.

We claim:
 1. A method comprising: serving by a base station one or morefirst user equipment devices (UEs) on just a first carrier; determiningby the base station that each of the one or more first UEs being servedon just the first carrier is receiving, from the base station on thefirst carrier, a quality of service level that is lower than a thresholdquality of service level; and responsive to the determining, (i)selecting by the base station one or more second UEs based on the one ormore second UEs being served by the base station on both the firstcarrier and one or more other carriers and, (ii) based on the selecting,discontinuing by the base station serving each selected second UE on thefirst carrier while continuing to serve each selected second UE on oneor more other carriers.
 2. The method of claim 1, wherein the basestation has a radio-link layer connection respectively with each firstUE and with each second UE, wherein the base station's radio-link layerconnection with each first UE encompasses just the first carrier, andthe base station's radio-link layer connection with each second UEencompasses the first carrier and one or more other carriers, andwherein discontinuing serving each selected second UE on the firstcarrier while continuing to serve each selected second UE on one or moreother carriers comprises removing from the radio-link layer connectionof each selected second UE the first carrier while maintaining one ormore other carriers in the radio-link layer connection of each selectedsecond UE.
 3. The method of claim 1, wherein the base station has aradio-link layer connection respectively with each first UE and witheach second UE, wherein the base station's radio-link layer connectionwith each first UE encompasses just the first carrier, and the basestation's radio-link layer connection with each second UE encompassesthe first carrier and one or more other carriers, and whereindiscontinuing serving each selected second UE on the first carrier whilecontinuing to serve each selected second UE on one or more othercarriers comprises discontinuing scheduling and communicating with eachselected second UE on the first carrier, though maintaining the firstcarrier in the radio-link layer connection of each selected second UE.4. The method of claim 1, wherein selecting by the base station one ormore second UEs based on the one or more second UEs being served by thebase station on both the first carrier and one or more other carrierscomprises: selecting the one or more second UEs based on the one or moresecond UEs being served by the base station with carrier aggregationservice using (i) the first carrier as a secondary carrier and (ii)another carrier as a primary carrier.
 5. The method of claim 4, furthercomprising: after discontinuing by the base station serving eachselected second UE on the first carrier while continuing to serve eachselected second UE on one or more other carriers, making a furtherdetermination that at least one of the first UEs being served on justthe first carrier is still receiving, from the base station on the firstcarrier, a quality of service level that is lower than the thresholdquality of service level; in response to making the furtherdetermination, (i) further selecting an additional one or more secondUEs based on the selected additional one or more second UEs being servedby the base station with carrier aggregation service using (a) the firstcarrier as a primary carrier and (b) one or more other carriers assecondary carriers and, (ii) based on the further selecting,discontinuing by the base station serving the selected additional one ormore second UEs on the first carrier while continuing to serve theselected additional one or more second UEs on one or more othercarriers.
 6. The method of claim 5, wherein discontinuing by the basestation serving the selected additional one or more second UEs on thefirst carrier while continuing to serve the selected additional one ormore second UEs on one or more other carriers comprises: causing thebase station to serve the selected additional one or more second UEswith carrier aggregation service using another carrier as primarycarrier; and after causing the base station to serve the selectedadditional one or more second UEs with carrier aggregation service usinganother carrier as primary carrier, discontinuing the serving of theselected additional one or more second UEs on the first carrier.
 7. Themethod of claim 1, wherein the quality of service level is defined basedat least in part on a metric selected from the group consisting ofthroughput, packet loss, jitter, and voice quality.
 8. A non-transitorycomputer readable medium having stored thereon instructions executableby a processor to cause a base station to perform operations comprising:serving one or more first user equipment devices (UEs) on just a firstcarrier; determining that each of the one or more first UEs being servedon just the first carrier is receiving, from the base station on thefirst carrier, a quality of service level that is lower than a thresholdquality of service level; and responsive to the determining, (i)selecting one or more second UEs based on the one or more second UEsbeing served by the base station on both the first carrier and one ormore other carriers and, (ii) based on the selecting, discontinuingserving each selected second UE on the first carrier while continuing toserve each selected second UE on one or more other carriers.
 9. Thenon-transitory computer readable medium of claim 8, wherein the basestation has a radio-link layer connection respectively with each firstUE and with each second UE, wherein the base station's radio-link layerconnection with each first UE encompasses just the first carrier, andthe base station's radio-link layer connection with each second UEencompasses the first carrier and one or more other carriers, andwherein discontinuing serving each selected second UE on the firstcarrier while continuing to serve each selected second UE on one or moreother carriers comprises removing from the radio-link layer connectionof each selected second UE the first carrier while maintaining one ormore other carriers in the radio-link layer connection of each selectedsecond UE.
 10. The non-transitory computer readable medium of claim 8,wherein the base station has a radio-link layer connection respectivelywith each first UE and with each second UE, wherein the base station'sradio-link layer connection with each first UE encompasses just thefirst carrier, and the base station's radio-link layer connection witheach second UE encompasses the first carrier and one or more othercarriers, and wherein discontinuing serving each selected second UE onthe first carrier while continuing to serve each selected second UE onone or more other carriers comprises discontinuing scheduling andcommunicating with each selected second UE on the first carrier, thoughmaintaining the first carrier in the radio-link layer connection of eachselected second UE.
 11. The non-transitory computer readable medium ofclaim 8, wherein selecting one or more second UEs based on the one ormore second UEs being served by the base station on both the firstcarrier and one or more other carriers comprises: making a determinationof whether the base station is serving at least one UE of the one ormore second UEs with carrier aggregation service using (i) the firstcarrier as a secondary carrier and (ii) another carrier as a primarycarrier; if the determination is that the base station is serving atleast one UE of the one or more second UEs with carrier aggregationservice using (i) the first carrier as a secondary carrier and (ii)another carrier as a primary carrier, then, responsive to making thedetermination, selecting the at least one UE based on the at least oneUE being served by the base station with carrier aggregation serviceusing (i) the first carrier as a secondary carrier and (ii) anothercarrier as a primary carrier; and if the determination is that that thebase station is not serving at least one UE of the one or more secondUEs with carrier aggregation service using (i) the first carrier as asecondary carrier and (ii) another carrier as a primary carrier, then,responsive to making the determination, instead selecting at least oneother UE of the one or more second UEs based on the at least one otherUE being served by the base station with carrier aggregation serviceusing (i) the first carrier as a primary carrier and (ii) one or moreother carriers as secondary carriers.
 12. The non-transitory computerreadable medium of claim 11, wherein the discontinuing of serving eachselected second UE on the first carrier while continuing to serve eachselected second UE on one or more other carriers comprises: if thedetermination is that that the base station is not serving at least oneUE of the one or more second UEs with carrier aggregation service using(i) the first carrier as a secondary carrier and (ii) another carrier asa primary carrier, then, responsive to making the determination, (a)causing the base station to serve each selected second UE with carrieraggregation service using another carrier as primary carrier and (b)after causing the base station to serve each selected second UE withcarrier aggregation service using another carrier as primary carrier,discontinuing the serving of each selected second UE on the firstcarrier.
 13. The non-transitory computer readable medium of claim 8,wherein the quality of service level is defined based at least in parton a metric selected from the group consisting of throughput, packetloss, jitter, and voice quality.
 14. A wireless communication systemcomprising: a base station; and a controller configured to cause thebase station to perform operations comprising: serving one or more firstuser equipment devices (UEs) on just a first carrier frequency;determining that each of the first UEs being served on just the firstcarrier frequency is receiving, from the base station on the firstcarrier frequency, a quality of service level that is lower than athreshold quality of service level; and responsive to the determining,(i) selecting one or more second UEs based on the one or more second UEsbeing served by the base station on both the first carrier frequency andone or more other carrier frequencies and, (ii) based on the selecting,discontinuing serving of each selected second UE on the first carrierfrequency while continuing to serve each selected second UE on one ormore other carrier frequencies.
 15. The wireless communication system ofclaim 14, wherein the base station has a radio-link layer connectionrespectively with each first UE and with each second UE, wherein thebase station's radio-link layer connection with each first UEencompasses just the first carrier, and the base station's radio-linklayer connection with each second UE encompasses the first carrier andone or more other carriers, and wherein discontinuing serving eachselected second UE on the first carrier while continuing to serve eachselected second UE on one or more other carriers comprises removing fromthe radio-link layer connection of each selected second UE the firstcarrier while maintaining one or more other carriers in the radio-linklayer connection of each selected second UE.
 16. The wirelesscommunication system of claim 14, wherein the base station has aradio-link layer connection respectively with each first UE and witheach second UE, wherein the base station's radio-link layer connectionwith each first UE encompasses just the first carrier, and the basestation's radio-link layer connection with each second UE encompassesthe first carrier and one or more other carriers, and whereindiscontinuing serving each selected second UE on the first carrier whilecontinuing to serve each selected second UE on one or more othercarriers comprises discontinuing scheduling and communicating with eachselected second UE on the first carrier, though maintaining the firstcarrier in the radio-link layer connection of each selected second UE.17. The wireless communication system of claim 14, wherein selecting bythe base station one or more second UEs based on the one or more secondUEs being served by the base station on both the first carrier and oneor more other carriers comprises: selecting the one or more second UEsbased on the one or more second UEs being served by the base stationwith carrier aggregation service using (i) the first carrier as asecondary carrier and (ii) another carrier as a primary carrier.
 18. Thewireless communication system of claim 14, wherein the controller isfurther configured to perform operations comprising: after discontinuingserving of each selected second UE on the first carrier frequency whilecontinuing to serve each selected second UE on one or more other carrierfrequencies, initiating a timer defining a duration of time for whichthe base station should discontinue serving each selected second UE onthe first carrier frequency; detecting expiration of the timer; and inresponse to detecting expiration of the timer, causing the base stationto again serve each selected second UE on both the first carrierfrequency and one or more other carrier frequencies.
 19. The wirelesscommunication system of claim 18, wherein the controller is furtherconfigured to perform operations comprising: after causing the basestation to again serve each selected second UE on both the first carrierfrequency and one or more other carrier frequencies, making adetermination of whether each of the first UEs being served on just thefirst carrier frequency is still receiving, from the base station on thefirst carrier frequency, a quality of service level that is lower thanthe threshold quality of service level; if the determination is thateach of the first UEs being served on just the first carrier frequencyis no longer receiving, from the base station on the first carrierfrequency, a quality of service level that is lower than the thresholdquality of service level, then, responsive to making the determination,resuming the serving of each selected second UEs on both the firstcarrier frequency and one or more other carrier frequencies; and if thedetermination is that at least one of the first UEs being served on justthe first carrier frequency is still receiving, from the base station onthe first carrier frequency, a quality of service level that is lowerthan the threshold quality of service level, then, responsive to makingthe determination, (i) additionally selecting one or more second UEsbased on the one or more second UEs being served by the base station onboth the first carrier frequency and one or more other carrierfrequencies and, (ii) based on the selecting, discontinuing serving ofeach additionally selected second UE on the first carrier frequencywhile continuing to serve each additionally selected second UE on one ormore other carrier frequencies.
 20. The wireless communication system ofclaim 14, wherein the quality of service level is defined based at leastin part on a metric selected from the group consisting of throughput,packet loss, jitter, and voice quality.